Before synthetic fiber finishes are deemed acceptable for use on filaments, yarns, and the like, they are subjected to close scrutiny. For instance, it is important to know with respect to finishes, such as lubricant compositions, their compatibility with the filamentary substrate; their ability to promote fiber bundle cohesion and enhance interfilament friction characteristics; their effect, deleterious or not, on dyeability, fiber strength or moisture level; their ability to counter flaring; their fiber/metal lubrication behavior; their manufacturing drawing processing and false twisting processing characteristics; their stability and durability, characteristics which are very helpful in avoiding handling or processing difficulties, particularly at high speeds for long periods of time and under a number of changing conditions, such as temperatures, stresses, running tensions, moisture, and the like; and their penchant, if any, for becoming viscous or tacky under these varying conditions, thus creating severe running tensions and, possibly, inordinate deposition characteristics.
Still another criterion has been imposed on finish compositions by dint of modern textile processing equipment. False twist texturing equipment, for example, has certain parts, such as cots and aprons, generally constructed of polyurethane resins which are sensitive to otherwise acceptable finish compositions. Experience has shown that these finishes, containing as they do emulsifiers of the nature of alkoxylated aliphatic or aromatic alcohols, fatty acids and partial esters of each, along with antistats of neutral salts of alcohol phosphate esters, quanternary ammonium salts, amines and amides, cause belt swelling, i.e., they attack and deteriorate polyurethane feed aprons and cots. Not only does this cause increased belt maintenance and replacement costs, but reduced yarn quality as well. Obviously, yarn could run longer with less belt maintenance, the number of snags and broken filaments could be minimized, thus enhancing yarn quality, if finish attack could be obviated.
The present invention is directed to finish compositions which are not only compatible with the yarn but which substantially enhance its processing characteristics. The enhancement is characterized as well by the insensitivity of certain texturing equipment parts to the unqiue finish compositions of the present invention.
Of interest are the following patents: U.S. Pat. No. 3,306,850 and U.S. Pat. No. 3,428,560.